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Publication numberUS6601647 B2
Publication typeGrant
Application numberUS 10/005,266
Publication dateAug 5, 2003
Filing dateDec 3, 2001
Priority dateDec 3, 2001
Fee statusLapsed
Also published asCA2413311A1, CA2413311C, EP1316539A2, EP1316539A3, US6631766, US6648961, US6660078, US20030101911, US20030101912, US20030101913, US20030101914
Publication number005266, 10005266, US 6601647 B2, US 6601647B2, US-B2-6601647, US6601647 B2, US6601647B2
InventorsLance E. Brothers, Krista L. Keener, James A. Braden
Original AssigneeHalliburton Energy Services, Inc.
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Sealing pipe in well bore penetrating zone; placing hydraulic cement, water, and suspension of microspheres in water gelled with sodium bentonite; hardening
US 6601647 B2
Abstract
The present invention provides methods, lightweight well cement compositions and additives for the well cement compositions. The methods of the invention for sealing pipe in a well bore penetrating a zone or formation which readily fractures at low hydrostatic pressure is basically comprised of the steps of providing a lightweight cement composition comprised of a hydraulic cement, water and an additive comprising a suspension of microspheres in water gelled with sodium bentonite, placing the cement composition in the annulus between the pipe and the well bore and allowing the cement composition to set.
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Claims(29)
What is claimed is:
1. A method of sealing pipe in a well bore penetrating a zone or formation which readily fractures at low hydrostatic pressures comprising the steps of:
(a) providing a lightweight cement composition comprised of a hydraulic cement, water and an additive comprising a suspension of microspheres in water gelled with sodium bentonite;
(b) placing said cement composition between the exterior surfaces of said pipe and the walls of said well bore; and
(c) allowing said cement composition to set into a hard impermeable mass.
2. The method of claim 1 wherein said hydraulic cement in said composition is selected from the group consisting of Portland cements, slag cements, pozzolana cements, gypsum cements, aluminous cements and silica cements.
3. The method of claim 1 wherein said hydraulic cement is Portland cement.
4. The method of claim 1 wherein said water is selected from the group consisting of fresh water, unsaturated salt solutions and saturated salt solutions.
5. The method of claim 1 wherein said water is present in said composition in an amount in the range of from about 60% to about 250% by weight of hydraulic cement therein.
6. The method of claim 1 wherein said additive is present in said composition in an amount in the range of from about 30% to about 100% by weight of hydraulic cement therein.
7. The method of claim 1 wherein said microspheres are fly ash microspheres.
8. The method of claim 1 wherein said microspheres are present in said additive in an amount in the range of from about 30% to about 48% by weight of said additive.
9. The method of claim 1 wherein said sodium bentonite is present in said additive in an amount in the range of from about 1% to about 2% by weight of said additive.
10. The method of claim 1 wherein said water is present in said additive in an amount in the range of from about 50% to about 69% by weight of said additive.
11. A method of sealing in a subterranean formation comprising the steps of:
(a) providing a cement composition comprising a hydraulic cement, water and an additive comprising a suspension of microspheres in water gelled with sodium bentonite;
(b) placing said cement composition in the formation; and
(c) allowing said cement composition to set.
12. The method of claim 11 wherein said hydraulic cement in said composition is selected from the group consisting of Portland cements, slag cements, pozzolana cements, gypsum cements, aluminous cements and silica cements.
13. The method of claim 11 wherein said hydraulic cement is Portland cement.
14. The method of claim 11 wherein said water is selected from the group consisting of fresh water, unsaturated salt solutions and saturated salt solutions.
15. The method of claim 11 wherein said water is present in said composition in an amount in the range of from about 60% to about 250% by weight of hydraulic cement therein.
16. The method of claim 11 wherein said additive is present in said composition in an amount in the range of from about 30% to about 100% by weight of hydraulic cement therein.
17. The method of claim 11 wherein said microspheres are fly ash microspheres.
18. The method of claim 11 wherein said microspheres are present in said additive in an amount in the range of from about 30% to about 48% by weight of said additive.
19. The method of claim 11 wherein said sodium bentonite is present in said additive in an amount in the range of from about 1% to about 2% by weight of said additive.
20. The method of claim 11 wherein said water is present in said additive in an amount in the range of from about 50% to about 69% by weight of said additive.
21. A method of sealing in a subterranean formation comprising the steps of:
(a) providing a lightweight cement composition comprising a hydraulic cement, water, and an additive present in said cement composition in an amount in the range of from about 30% to about 100% by weight of hydraulic cement wherein said additive comprises a suspension of microspheres in water gelled with sodium bentonite;
(b) placing said cement composition in the formation; and
(a) allowing said cement composition to set.
22. The method of claim 21 wherein said hydraulic cement in said composition is selected from the group consisting of Portland cements, slag cements, pozzolana cements, gypsum cements, aluminous cements and silica cements.
23. The method of claim 21 wherein said hydraulic cement is Portland cement.
24. The method of claim 21 wherein said water is selected from the group consisting of fresh water, unsaturated salt solutions and saturated salt solutions.
25. The method of claim 21 wherein said water is present in said composition in an amount in the range of from about 60% to about 250% by weight of hydraulic cement therein.
26. The method of claim 21 wherein said microspheres are fly ash microspheres.
27. The method of claim 21 wherein said microspheres are present in said additive in an amount in the range of from about 30% to about 48% by weight of said additive.
28. The method of claim 21 wherein said sodium bentonite is present in said additive in an amount in the range of from about 1% to about 2% by weight of said additive.
29. The method of claim 21 wherein said water is present in said additive in an amount in the range of from about 50% to about 69% by weight of said additive.
Description
BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to methods, compositions and lightweight additives for sealing pipe strings in well bores, and more particularly, to such methods, compositions and additives wherein the well bores penetrate formations that readily fracture at low hydrostatic pressures.

2. Description of the Prior Art

Hydraulic cement compositions are commonly utilized in oil, gas and water well completion and remedial operations. For example, hydraulic cement compositions are used in primary cementing operations whereby strings of pipe such as casing and liners are cemented in well bores. In performing primary cementing, a hydraulic cement composition is pumped into the annular space between the walls of a well bore and the exterior of a string of pipe disposed therein. The cement composition is permitted to set in the annular space thereby forming an annular sheath of hardened substantially impermeable cement therein. The cement sheath physically supports and positions the pipe in the well bore and bonds the pipe to the walls of the well bore whereby the undesirable migration of fluids between zones or formations penetrated by the well bore is prevented.

In some well locations, the subterranean zones or formations into or through which wells are drilled have high permeabilities and low compressive and tensile strengths. As a result, the resistance of the zones or formations to shear are low and they have low fracture gradients. When a hydraulic cement composition is introduced into a well bore penetrating such a subterranean zone or formation, the hydrostatic pressure exerted on the walls of the well bore can exceed the fracture gradient of the zone or formation and cause fractures to be formed in the zone or formation into which the cement composition is lost. While lightweight cement compositions have been developed and used, subterranean zones or formations are often encountered which have fracture gradients too low for the lightweight cement compositions to be utilized without the formation of fractures and the occurrence of lost circulation problems.

Thus, there are needs for improved lightweight cement compositions for sealing pipe such as casings and liners in well bores which penetrate zones or formations having very low fracture gradients.

SUMMARY OF THE INVENTION

The present invention provides lightweight well cement compositions, additives for use in the compositions and methods of using the lightweight compositions for sealing pipe in well bores penetrating zones or formations having low fracture gradients which meet the needs described above and overcome the deficiencies of the prior art. The methods of this invention basically comprise the steps of providing a lightweight cement composition comprised of a hydraulic cement, water and an additive comprising a suspension of microspheres in water gelled with sodium bentonite. The cement composition is placed into the annulus between a pipe and the walls of a well bore and the sealing composition is allowed to set into a hard impermeable mass.

A lightweight sealing composition of this invention is basically comprised of a hydraulic cement, water and an additive for making the cement composition lightweight. The additive utilized in accordance with this invention is comprised of a suspension of microspheres in water gelled with sodium bentonite.

It is, therefore, a general object of the present invention to provide methods, lightweight well cement compositions and additives for use in cementing pipe in well bores.

Other and further objects, features and advantages of the present invention will be readily apparent to those skilled in the art upon a reading of the description of preferred embodiments which follows.

DESCRIPTION OF PREFERRED EMBODIMENTS

By the present invention, methods, lightweight well cement compositions and additives therefor are provided for sealing pipes in well bores penetrating zones or formations which readily fracture at low hydrostatic pressures. The methods of this invention for sealing a pipe in a well bore penetrating a zone or formation which readily fractures at low hydrostatic pressures is basically comprised of providing a lightweight cement composition comprised of a hydraulic cement, water and an additive comprising a suspension of microspheres in water gelled with sodium bentonite. The lightweight cement composition is placed into the annulus between the exterior surfaces of the pipe and the walls of the well bore and the cement composition is allowed to set into a hard impermeable mass therein.

A variety of hydraulic cements can be utilized in accordance with the present invention including those comprised of calcium, aluminum, silicon, oxygen and/or sulfur which set and harden by reaction with water. Such hydraulic cements include Portland cements, slag cements, pozzolana cements, gypsum cements, aluminous cements and silica cements. Portland cements or their equivalents are generally preferred for use in accordance with the present invention. Portland cements of the types defined and described in the API Specification For Materials And Testing For Well Cements, API Specification 10, 5th Edition, dated Jul. 1, 1990 of the American Petroleum Institute are particularly suitable. Preferred API Portland cements include Classes A, B, C, G and H with Classes G and H being more preferred, and Class G being the most preferred.

The water utilized to form the foamed cement compositions of this invention can be fresh water, unsaturated salt solutions or saturated salt solutions. The water is included in the cement compositions of this invention in an amount in the range of from about 60% to about 250% by weight of hydraulic cement therein.

The additive which is included in the cement compositions of this invention to make the compositions lightweight is basically comprised of a suspension of microspheres in water gelled with sodium bentonite. While various microspheres can be utilized, fly ash microspheres are preferred for use in the present invention. Particularly suitable such fly ash microspheres are commercially available from Halliburton Energy Services, Inc. of Duncan, Okla. under the tradename “SPHERELITE™”. Another type of microspheres that can be used is synthetic hollow glass microspheres commercially available from Minnesota Mining and Manufacturing Company (3M™) under the tradename “SCOTCHLITE™”. These very low density microspheres are formed of a chemically stable soda-lime borosilicate glass composition which is non-porous. The microspheres used are included in the water gelled with sodium bentonite in a general amount in the range of from about 30% to about 100% by weight of the water. Preferably, the microspheres are included in the gelled water in an amount of about 67% by weight of the water therein. The sodium bentonite hydrates in the water and forms a stable gel in which the microspheres do not float. The sodium bentonite is included in the water in an amount in the range of from about 1% to about 4% by weight of the water, preferably an amount of about 2% by weight of the water.

As will be understood by those skilled in the art, various conventional additives can be included in the lightweight sealing compositions of this invention including, but not limited to, set retarders, set accelerators, fluid loss control additives and dispersants.

A preferred method of this invention for sealing pipe in a well bore penetrating a zone or formation which readily fractures at low hydrostatic pressures is comprised of the steps of: (a) providing a lightweight cement composition comprised of a hydraulic cement, water and an additive comprising a suspension of microspheres in water gelled with sodium bentonite; (b) placing the cement composition between the exterior surfaces of the pipe and the walls of the well bore; and (c) allowing the cement composition to set into a hard impermeable mass.

A more preferred method of the present invention for sealing pipe in a well bore penetrating a zone or formation which readily fractures at low hydrostatic pressures is comprised of the steps of: (a) providing a lightweight cement composition comprised of a hydraulic cement, water present in the composition in an amount in the range of from about 60% to about 250% by weight of the hydraulic cement therein and an additive comprising a suspension of fly ash microspheres in water gelled with sodium bentonite present in the composition in an amount in the range of from about 30% to about 100% by weight of hydraulic cement therein; (b) placing the cement composition into the annulus between the pipe and the walls of the well bore; and (c) allowing the cement composition to set into a hard impermeable mass.

A preferred lightweight well cement composition of this invention is comprised of: a hydraulic cement; water selected from the group of fresh water, unsaturated salt solutions and saturated salt solutions present in an amount in the range of from about 60% to about 250% by weight of the hydraulic cement in the composition; and an additive comprised of a suspension of microspheres in water gelled with sodium bentonite present in an amount in the range of from about 30% to about 100% by weight of hydraulic cement in the composition.

A preferred lightweight cement composition additive of this invention is comprised of: a suspension of microspheres in water gelled with sodium bentonite.

A more preferred lightweight cement composition additive of this invention is comprised of: a suspension of fly ash microspheres in water gelled with sodium bentonite, the fly ash microspheres being present in an amount in the range of from about 30% to about 48% by weight of the additive; the sodium bentonite being present in an amount in the range of from about 1% to about 2% by weight of the additive; and the water being present in an amount in the range of from about 50% to about 69% by weight of the additive.

The most preferred lightweight cement composition additive of this invention is comprised of: a suspension of fly ash microspheres in a water solution of sodium bentonite, the microspheres being present in an amount of about 40% by weight of the additive; the sodium bentonite being present in an amount of about 1.2% by weight of the additive; and the water being present in an amount of about 58.8% by weight of the additive.

In order to further illustrate the methods, the lightweight well cement compositions and the additives of this present invention, the following examples are given.

EXAMPLE

A lightweight additive of this invention was prepared by hydrating 20 grams of sodium bentonite in 1000 grams of water. To 600 grams of the resulting water gelled with sodium bentonite, 400 grams of fly ash microspheres were added. 300 grams of Portland cement were then mixed with 300 grams of the lightweight additive and 150 grams of fresh water. The resulting cement slurry was subjected to 4000 psi of pressure to simulate the hydraulic pressure at the bottom of a well bore. After being subjected to the applied pressure, the density of the slurry was 11.2 lb/gal. The slurry was poured into a plexiglass tube measuring 12 inches in length and 1.75 inches internal diameter. The slurry was then allowed to set to form a hardened mass after which a one inch section was cut from the top and bottom of the plexiglass tube. The hardened cement was removed from the one inch sections of the tube and their densities determined. The density of the bottom section was 11.1 lb/gal and the density of the top section was 11.3 lb/gal. This shows that, within experimental error, the cement was uniform in density and the experimental liquid additive was effective in preparing a lightweight cement.

Thus, the present invention is well adapted to carry out the objects and attain the ends and advantages mentioned as well as those which are inherent therein. While numerous changes may be made by those skilled in the art, such changes are encompassed within the spirit of this invention as defined by the appended claims.

Patent Citations
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Non-Patent Citations
Reference
1Halliburton brochure entitled "Spherelite Cement Additive" dated 1999.
2Paper entitled "Cementing" by Dwight K. Smith, pp. 21-27, 1990.
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US6811603 *Jun 25, 2003Nov 2, 2004Halliburton Energy Services, Inc.Methods, well cement compositions and lightweight additives therefor
US6983800Oct 29, 2003Jan 10, 2006Halliburton Energy Services, Inc.Methods, cement compositions and oil suspensions of powder
US7073584Nov 12, 2003Jul 11, 2006Halliburton Energy Services, Inc.Processes for incorporating inert gas in a cement composition containing spherical beads
US7111684Sep 14, 2004Sep 26, 2006Halliburton Energy Services, Inc.Biodegradability; hydraulic cement and invert emulsion of an oleaginous fluid, nonoleaginous fluid, and emulsifying surfactant (ether carboxylic acid)
US7147705Oct 5, 2005Dec 12, 2006Halliburton Energy Services, Inc.Slurry of hydraulic cement in water and an oil suspension of silica powder, mineral oil, an oleophilic clay, an oleophilic surfactant and a hydrophilic surfactant; eliminates silica powder and dust being produced during the handling and blending of silica with cement
US7316742Aug 7, 2006Jan 8, 2008Halliburton Energy Services, Inc.Biodegradability; hydraulic cement and invert emulsion of an oleaginous fluid, nonoleaginous fluid, and emulsifying surfactant (ether carboxylic acid)
US7373981Feb 14, 2005May 20, 2008Halliburton Energy Services, Inc.Methods of cementing with lightweight cement compositions
US7390356Mar 11, 2005Jun 24, 2008Halliburton Energy Services, Inc.cements comprising calcium aluminate, sodium polyphosphate and fly ash, water, retarders, antifoam agents, surfactants, latex and glass spheres, used for cementing subterranean zones; resistance to alkali carbonation induced deterioration and maintains its compressive strength and competency
US7393814Oct 5, 2006Jul 1, 2008Hallburton Energy Services, Inc.Methods, cement compositions and oil suspensions of powder
US7398827Mar 11, 2005Jul 15, 2008Halliburton Energy Services, Inc.Methods for high temperature lightweight cementing
US7510609Feb 8, 2005Mar 31, 2009Halliburton Energy Services Inc.comprising: a cement component; a density-reducing additive comprising particulates that comprise an agglomerating material; and a base fluid; particulate comprises fly ash
US7524369Feb 8, 2005Apr 28, 2009Halliburton Energy Services, Inc.adding to the cement a base fluid, a density-reducing additive comprising fly ash sparticles and agglomerating cement such as portland; pozzolana; gypsum cement; high alumina content cement; silica cement; high alkalinity cement; placing the cement to a location needs to be cemented, allowing to be set
US7604053Mar 11, 2008Oct 20, 2009Halliburton Energy Services, Inc.Methods of cementing with lightweight cement composition
US7757766Nov 19, 2008Jul 20, 2010Halliburton Energy Services, Inc.Treating a well bore penetrating a subterranean formation comprising combining components water and a density-matched suspension to prepare a treatment fluid; the density-matched suspension comprises a suspending liquid and a solid particle suspended in the suspending liquid; nonsettling
US7789149Nov 3, 2006Sep 7, 2010Halliburton Energy Services, Inc.Methods of servicing wellbore with composition comprising ultra low density thermatek® slurries
US7833344Nov 3, 2006Nov 16, 2010Halliburton Energy Services Inc.Ultra low density cement compositions and methods of making same
US8546310Jun 2, 2010Oct 1, 2013Halliburton Energy Services, Inc.Density-matched suspensions and associated methods
Classifications
U.S. Classification166/293
International ClassificationC09K8/46, C09K8/42, C04B28/02, C09K8/473
Cooperative ClassificationY10S106/01, Y10S106/04, C04B28/02, C09K8/46, C09K8/473, C09K8/42
European ClassificationC09K8/42, C09K8/46, C04B28/02, C09K8/473
Legal Events
DateCodeEventDescription
Sep 27, 2011FPExpired due to failure to pay maintenance fee
Effective date: 20110805
Aug 5, 2011LAPSLapse for failure to pay maintenance fees
Mar 14, 2011REMIMaintenance fee reminder mailed
Dec 18, 2006FPAYFee payment
Year of fee payment: 4
Dec 3, 2001ASAssignment
Owner name: HALLIBURTON ENERGY SERVICES, INC., TEXAS
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:BROTHERS, LANCE E.;KEENER, KRISTA L.;BRADEN, JAMES A.;REEL/FRAME:012371/0198;SIGNING DATES FROM 20011130 TO 20011203
Owner name: HALLIBURTON ENERGY SERVICES, INC. 10200 BELLAIRE B
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:BROTHERS, LANCE E. /AR;REEL/FRAME:012371/0198;SIGNING DATES FROM 20011130 TO 20011203